tree b972d364030b8f3cb9fea41e74127d9683666a9f
parent 43079e07316638c98acd04977fe156b338528d51
author Olivier Houchard <cognet@ci0.org> 1593777877 +0200
committer Willy Tarreau <w@1wt.eu> 1593791363 +0200
encoding latin1

BUG/MEDIUM: connections: Set the tid for the old tasklet on takeover.

In the various takeover() methods, make sure we schedule the old tasklet
on the old thread, as we don't want it to run on our own thread! This
was causing a very rare crash when building with DEBUG_STRICT, seeing
that either an FD's thread mask didn't match the thread ID in h1_io_cb(),
or that stream_int_notify() would try to queue a task with the wrong
tid_bit.

In order to reproduce this, it is necessary to maintain many connections
(typically 30k) at a high request rate flowing over H1+SSL between two
proxies, the second of which would randomly reject ~1% of the incoming
connection and randomly killing some idle ones using a very short client
timeout. The request rate must be adjusted so that the CPUs are nearly
saturated, but never reach 100%. It's easier to reproduce this by skipping
local connections and always picking from other threads. The issue
should happen in less than 20s otherwise it's necessary to restart to
reset the idle connections lists.

No backport is needed, takeover() is 2.2 only.